/Engine/Source/Runtime/MovieScene/Public/EntitySystem/MovieSceneEntityManager.h
Does not consider per-allocation overhead such as header sizes and other per-allocation meta-data
void CountMemory ( [FArchive](API\Runtime\Core\Serialization\FArchive) & Ar, [FMovieSceneEntityID](API\Runtime\MovieScene\EntitySystem\FMovieSceneEntityID) EntityID )